To study the effects of carbohydrate（ CHO） ingestion on intermittent fuel metabolism changes during prolonged treadmill walking, seven male subjects performed 120 minutes walking on a treadmill at a speed of 80m/min with （GLU） and without （CONT） glucose ingestion 1 hour prior to the exercise.During this experiment, blood samples were collected to analyze the concentrations of plasma glucose, lactate and triglyceride.Respiratory gas was carried into the gas analyzer to measure oxygen uptake （VO2）, elimination of carbon dioxide （VCO2） and pulmonary ventilation（ VE）.As a result, plasma glucose was significantly higher（ p<0.05） in GLU than CONT from the onset of the exercise to the period of 60 min.More contribution of fat oxidation was found in CONT than GLU during the exercise.The cross points that the contribution rates of CHO/fat oxidation were equal came at 40 min and 120 min in CONT and GLU,respectively.The oxidation rates were approximately 300 mg/min in both experiments and there were no significant difference in the volumes of whole oxidation rates between GLU and CONT during the exercise.These findings suggest that during prolonged walking at moderate speed a glucose ingestion prevents from consuming fat even after 120 min exercise.